Granulation process

ABSTRACT

A PROCESS FOR PRODUCING GRANULAR ENZYME PRODUCT CONTAINING ENZYME, A WATER-SOLUBLE, HYDRATABLE, BUILDER SALT, SUCH AS SODIUM TRIPOLYPHOSPHATE, AND A WATER-SOLUBLE, NONIONIC SURFACE ACTIVE AGENT WHICH COMPRISES GRANULATING THE ENZYME IN PARTICULATE FORM AND THE HYDRATABLE BUILDER SALT IN PARTICULATE FORM WITH A SOLUTION OF A WATER-SOLUBLE NONIONIC SURFACE ACTIVE MATERIAL IN WATER, THE WATER BEING PRESENT IN AT LEAST SUFFICIENT AMOUNT TO SUBSTANTIALLY COMPLETELY HYDRATE THE BUILDER SALT.

United States Patent 01 ftce 3,687,853 Patented Aug. 29, 1972 3,687,853 GRANULATION PROCESS Rcmigio Natali and Giuseppe Giombini, Rome, Italy, assiguors to Colgate-Palmolive Company, New York,

.Y. No Drawing. Filed June 2, 1970, Ser. No. 42,892 Claims priority, application Italy, June 6, 1969, 37 689 lint. Cl. (511d 7/42 US. Cl. 252-89 10 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method of making a granular, free-flowing, non-dusting, enzyme-containing composition having high enzyme activity and the method of using the composition in manufacturing enzyme-containing washing products.

Powdered enzymes have been employed in presoak and washing detergent compositions since they are particularly effective against various common stains which are fixed to textiles and laundry. In particular, proteolytic enzymes, which possess the ability to digest and degrade protein matter, are elfective in removing from textiles and laundry protein stains such as blood, sweat, milk, cocoa, gravy and other sauces and the like. This digestion or degradation of protein matter facilitates removal of dirt by the detergent. Amylases and lipases are also useful in detergent cleaning.

However, the use of powdered enzymes in such compositions has resulted in certain problems including the presence of an excessive amount of dust. Furthermore, detergent compositions containing enzymes have been subject to discoloration, formation of undesirable odor and caking.

It has been suggested to bind various compounds which are common builder salts in this hydratable form with enzymes. This may be done by contacting enzyme with an anhydrous or partially hydrated salt and adding water in insufficient amount to fully hydrate the salt. However, in such a process a considerable amount of enzyme dust is still present when the enzyme-hydratable salt composition is used. Discoloration and odor formation may occur also. Furthermore, the enzyme-partially hydrated builder salt compositions exhibit reduced enzyme activity when formulated as a component of certain heavy duty laundry products, apparently due to contact with materials which are deleterious to enzyme activity. For example, an enzyme-containing, heavy duty, laundry detergent composition Containing perborate bleach in contact with a moist atmosphere exhibits reduced enzyme activity.

It is an advantage of this invention to provide a stable, non-dusting granulate composition which has desirable color, is substantially free of unpleasant odor, is easy to handle without substantial degradation into lines, and has improved enzyme stability in the presence of bleach.

In accordance with certain of its aspects, this invention relates to a process for producing a granular enzyme product which comprises granulating enzyme in particulate form and a water-soluble, hydratable builder salt in particulate form with an aqueous solution of a water-soluble nonionic surface active agent, the amount of water in the solution being at least suflicient to substantially fully hydrate the hydratable salt.

An important characteristic of the described process is the step of using an aqueous nonionic surface active agent to granulate the enzyme and the hydratable builder salt. By employing an aqueous solution of the water-soluble, nonionic surface active agent, it appears that a stronger, less frangible, enzyme-containing granule is obtained. While the specific mode of action of the nonionic agent is not known, it is believed that the nonionic agent causes more of the enzyme to be attached to an interior surface of the water-soluble hydratable builder salt. It was discovered that the hydratable builder salt could be hydrated to contain to of theoretical amount of water in the stable builder salt hydrate. Thus, the higher moisture granules contain a lower amount of solids per unit of Weight and have a corresponding cost advantage.

The process of the invention may be carried out by premixing the enzyme and hydratable salt in a powder mixer or an air mixer and separately dissolving the nonionic agent in water in a tank with stirring. The aqueous nonionic solution is then sprayed onto the premix in a granulating mixer. The granulating mixer may be the well known Hobart mixer (whose mixing blade rotates about the blade axis and also moves in a circular path about the axis of the mixing vessel and close to the cylindrical internal wall of the mixing vessel) which has given smaller beads than the use of a conventional Day mixer (whose helical mixing blade also moves in a circular path about the axis of the mixing vessel and close to its cylindrical internal wall, but does not rotate about the blade axis). Other granulating mixers which may be used are the Patterson and Kelley Twin Shell Blender (whose mixing action is achieved by rotating the V-shaped vessel around a horizontal axis to obtain a dispersion of the aqueous nonionic solution throughout the moving mixture of enzyme and hydratable inorganic salt) and the Griin mixer (whose mixing is achieved by swirling or spiraling powdered materials in an updraft of air in a chamber and maintaining said mixture therein while spraying the swirling solids with aqueous nonionic from spray nozzles mounted around the lower periphery of the chamber). In the Griin mixer, the agglomerated product is not discharged from the mixing zone until the agglomerate achieves a size sufficient to overcome the force of the updraft of air. Other suitable granulating mixers are the granulating pans traditionally used by the pharmaceutical industry and the granulating drums used in the preparation of granular fertilizers.

The mixing period during the granulation step is variable and must be integrated with the proportions of the hydratable salt and the enzyme preparation, the degree of hydration of the hydratable salt, the concentration and degree of atomization of the nonionic solution, and the degree of mixing. Generally, a mixing period of about 3 to 11 minutes, preferably 5 to 9 minutes, is required to add and to substantially homogeneously disperse the nonionic solution throughout the hydratable salt-enzyme mixture so as to produce a substantially dry, non-dusty, enzyme-containing granule having the desired particle size.

Preferably, the process is carried out in such fashion as to produce beads or granules which pass through a 10 mesh screen (screen opening 2 mm), more preferably through a 20 mesh screen (screen. opening 0.84 mm.), and are retained on an 80 mesh screen (screen opening 0.177 mm.); the beads or granules within that size range more preferably constitute a major proportion (and most preferably being at least about 70%, e.g., about 70%- 85% of the total weight of the product). All screen sizes used herein are US. Standard.

In the preferred form of the invention the enzyme comprises a proteolytic enzyme which is active upon protein matter and catalyzes digestion or degradation of such matter when present as in linen or fabric stain in a hydrolysis reaction. Generally, the enzymes are effective in a pH range of about 4-12.

The enzyme preparations are generally diluted with inorganic salts, e.g., akali metal and alkaline earth metal salts. Typically the enzyme comprises from 1% to 80% by weight of the enzyme preparation. For example, a typical Alcalase enzyme material analyzes (by weight) 6.5% enzyme, 4% water, 70% sodium chloride, 15.5% sodium sulfate, 3.5% calcium sulfate, and 0.5% organic impurities. Chemically they are typically stable in the pH range of 5 to 10, particularly at an alkaline pH of 8.0 to 9. Generally, they are effective against various types of soil in an aqueous medium having a temperature of about 20 C. to about 80 C. Naturally, different proteolytic enzymes have different degrees of effectiveness in aiding in the removal of specific stains from textiles and linen.

Instead of, or in addition to, the proteolytic enzyme, an amylase may be present such as a bacterial amylase of the alpha type (e.g. obtained by fermentation of B. subtilis). One very suitable enzyme mixture contains both a bacterial amylase of the alpha type and an alkaline protease, preferably in proportions to supply about 100,- 000 to 400,000 Novo alpha-amylase units per Anson unit of said alkaline protease.

On a solids basis, i.e., a water-free basis, the enzyme preparation content of the granules or beads can be varied widely and generally will be in the range of 2%. to 50% by weight of enzyme preparation or 0.1% to 4% by weight of active enzyme. When the particulate enzyme preparation has an alkaline protease content of 1.5 Anson units per gram, this range of course represents some 3 to 75 Anson units per 100 grams of granules or beads. The invention finds its greatest utility, however, for the manufacture of granules or beads which are relatively rich in enzyme preparation content, containing at least by Weight of the enzyme preparation (corresponding to say at least Anson units per 100 grams of the granules) and preferably at least 15% by weight. In the final washing product, made for example by blending the enzyme containing granules or beads with other granular materials (such as spray-dried hollow beads or spongeous low density granules), the content of powdered enzyme preparation is much lower, e.g., in the range of about 0.10% to 4.0%, preferably about 0.3% to 2.0%.

The amount of the granular enzyme product present in the detergent composition will, of course, depend to some extent on the amount of the detergent composition which is to be added to the wash water. For detergent compositions which are intended for use at concentrations of, say, about 0.15% in the Wash water of an automatic home laundry machine, one suitable amount of granular enzyme product is such as to provide 1 Anson unit of the alkaline protease for each 100 to 500 (e.g., 200 to 400) grams of the detergent composition. Thus, in a heavyduty laundry detergent composition, the enzyme-containing granulate composition will form "about 0.3% to about 30%. by weight and the balance will be a mixture of synthetic organic detergent and water-soluble builder salts wherein the ratio of detergent to builder salts is in the range of 1:2 to 1:10 by weight.

Generally, the water-soluble, hydratable builder salts used in the process of this invention provide a pH in the range of 4 to 12, preferably in the range of 7 to 11. The water-soluble hydratable builder salt component may be a single salt, a mixture of hydratable salts, a mixture of a hydratable salt with non-hydratable, water-soluble builder salts, or a portion of a multi-component detergent granule.

The particules of hydratable builder salt which are mixed with the powdered enzyme generally range in particle size from about 0.044 mm. to about 3.36 mm., i.e., corresponds to a US. Sieve range of 6 mesh to +325 mesh. Since these salts contain more fines than the typical spray dried detergent products which range from about 0.2 mm. to 2.0 mm. they are more prone to dusting. Therefore, the preferred size range of the builder salt is 0.2 mm. to 2.0 mm., with a preferred density range of 0.2 to 1.0 grams/cc.

Typical examples of hydratable organic builder salts which may be employed alone or in the aforementioned admixtures include the trisodium salt of nitrilotriacetic acid and the di-, triand tetrasodium salts of ethylenediamine tetraacetic acid. Preferred inorganic hydratable builder salts are the alkali metal polyphosphate salts which have the property of inhibiting precipitation of calcium and magnesium material in aqueous solution and of contributing to the heavy-duty performance of the detergent product. They may be considered as derived from orthophosphoric acid or the like by the removal of molecularly-bound water, though any suitable means of manufacture may be employed if desired. Such complex or molecularly dehydrated polyphosphate salts may be used in the form of the normal or completely neutralized salt, e.g. pentapotassium tripolyphosphate, pentasodium tripolyphosphate, and potassium acid tripolyphosphate. The alkali metal salts of tetraphosphoric acid may be used also. The alkali metal polyphosphate salts may be used in either anhydrous form or partially hydrated form.

Other hydratable alkaline builder salts may be employed also, such as the soluble alkali metal borates, sulfates, carbonates, and silicates. Usually, the silicates will be employed in suitable combination with other hydratable builder salts such as the polyphosphates. Suitable silicates are those available in solid form and having an alkali oxide to silicon dioxide ratio within the range of about 1:1 to 1:4, and preferably from about 1:2 to 1:3. Examples are sodium silicates having an Na O' to SiO ratio of 1:235, 1:25, 1:32, 1:2.0, 1:1.6 and 1:1. The sodium and potassium hydratable builder salts are preferred, and the most highly preferred builder salt is anhydrous sodium tripolyphosphate.

The hydratable builder salt content of the granulate of the invention can be varied widely, for example, in the range of about 20-97% by weight of the granulate on a solids basis, i.e., a water-free basis. Typically, it is present in the range of about 40-90% by weight on a solids basis.

The water-soluble nonionic surface active agent which is dissolved in water and then granulated with the premix of enzyme and hydratable builder salt may be in the form of a liquid, paste or solid at room temperature. Such nonionic synthetic organic detergents are generally the condensation product of an organic aliphatic or alkyl aromatic hydrophobic compound and hydrophilic ethylene oxide groups or, with the polyhydration product thereof, polyethylene glycol. Practically any hydrophobic compound having a carboxy, hydroxy, amido or amino group with a free hydrogen attached to the nitrogen can be condensed with ethylene oxide to form a nonionic detergent. Further, the length of the polyethenoxy chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic elements.

The nonionic detergents include the polyethylene oxide condensate of one mole of alkyl phenol containing from about 6 to about 12 carbon atoms in a straight or branched chain configuration with about to 30 moles of ethylene oxide, e.g., nonyl phenol condensed with 9 moles of ethylene oxide, dodecyl phenol condensed with 15 moles of ethylene oxide, and dinonyl phenol condensed with 15 moles of ethylene oxide. Condensation products of the corresponding alkyl thiophenol with 6 to 30 moles of ethylene oxide are also suitable.

Also included in the nonionic detergent class are the condensation products of a higher alcohol containing about 8 to 22 carbon atoms in a straight or branched chain configuration condensed with about 5 to 30 moles of ethylene oxide, e.g., lauryl-myristyl alcohol condensed with 16 moles of ethylene oxide.

Another well known class of nonionic detergents is the condensation product of ethylene oxide on a hydrophobic base formed by the condensation of propylene oxide and propylene glycol. These materials are sold under the trade name Pluronic. The molecular weight of the hydrophobe ranges from about 1,500 to 1,800 and the polyethylene oxide content may comprise up to 50% of the total weight of the condensate.

Other nonionic detergents include the ethylene oxide addends of monoesters of hexahydric alcohols and inner ethers thereof with higher fatty acids containing about 10 to 20 carbon atoms, e.g., sorbitan monolaurate, sorbitan mono-oleate, and mannitan monopalmitate.

The nonionic agent content of the granulate of the invention can be varied, e.g., in the range of about 1 to 25%, preferably about 2 to 20% and most preferably about 2.5 to 5% on a solids basis. The liquid nonionic detergents are preferred and the most highly preferred detergents are the liquid alkyl phenol ethylene oxide condensates and the liquid higher alcohol ethylene oxide condensates. The concentration of nonionic detergent in the aqueous solution is usually in the range of about 4% to 30% by weight, since such solutions exhibit relatively low viscosities and atomize readily.

As stated heretofore, the presence of the nonionic agent in the Water during the granulation process of the invention imparts certain advantageous characteristics to the granulate over those characteristics which would be present if the nonionic agent were not employed or were employed in the premix of enzyme and hydratable builder salt.

The granulate composition is expressed on a solids basis because the amount of water present varies with the identity and the amount of each particular hydratable salt. For example, 0.294 part by weight of water are required for each part of anhydrous sodium tripolyphosphate if the stable sodium tripolyphosphate hexahydrate is formed, whereas, 1.26 parts by weight of water are required for each part of sodium sulfate if the stable sodium sulfate decahydrate is formed. For this reason the granulate composition comprising enzyme preparation attached to a substantially completely hydrated hydratable salt is specified as containing (a) 2 to 50% by weight of enzyme preparation on a solids basis, (b) 20 to 97% of a hydratable salt, i.e., anhydrous or partially hydrated hydratable salt, on a solids basis, ((2) l to 25% by weight of nonionic surface active agent on a solids basis, and ((1) water in an amount sufficient to substantially completely hydrate said hydratable salt to produce a hydrate thereof containing about 95 to about 130% of the theoretical amount of water in the completely hydrated salt. To the extent that the amount of water exceeds the water in the fully hydrated salt, the water will be free water. From the foregoing it is apparent that, in the absence of other ingredients, the composition of the granulate on a solids basis is identical to the composition of the mixture of enzyme preparation, hydratable salt, and nonionic agent.

The enzyme-containing granulate produced in accordance with this invention may appear in a wide variety of washing products. For example, the granulate may be incorporated in a laundry presoak product or in a laundry detergent or in a dishwashing product. The granulate may be used as a laundry presoak product or it may be admixed with additional builders and a small amount of organic detergent to form a laundry presoak product. A typical presoak product contains a relatively high concentration of builder salt such as about 30 to pentasodium tripolyphosphate (calculated as anhydrous penta sodium tripolyphosphate), about 2 to 10% of organic surface active detergent, plus other ingredients such as sodium silicate (which acts as a builder salt and also acts to inhibit corrosion of aluminum surfaces), brightening agents and sodium sulfate. A laundry detergent generally has a lower ratio of builder salt to organic surface active agent (e.g., a ratio in the range of about 1:1 to 10:1 and preferably in the range of 2: 1-611). On the other hand, dishwashing products designed for use in automatic dishwashers are usually more alkaline, containing a very high proportion of alkaline builder salt, such as a mixture of the pentasodium tripolyphosphate and sodium silicate; they contain little, if any, organic surface active detergent, e.g., about 0.2 to 3%. Usually, automatic dishwashing compositions contain a minor proportion (e.g., 0.5 to 5%) of an agent to prevent water-spotting such as a dry watersoluble compound which on contact with Water, liberates hypochlorite chlorine (e.g., a heterocyclic dichloroisocyanurate); alternatively, a chlorinated phosphate (such as the well known chlorinated trisodium phosphate) may be used to supply both hypochlorite chlorine and some phosphate.

In formulating the washing products, the water-soluble builder salts usually employed are the phosphates and particularly condensed phosphates (e.g., pyrophosphates or tripolyphosphates), silicates, borates and carbonates (including bicarbonates), as well as organic builders such as salts of nitrilotriacetic acid or ethylene diamine tetraacetic acid. Sodium and potassium salts are preferred. Specific examples are sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, sodium car bonate, sodium bicarbonate, sodium sesquicarbonate, sodium tetrahorate, sodium silicate, salts (e.g., Na salt) of methylene diphosphonic acid, disodium diglycollate, trisodium nitrilotriacetate, or mixtures of such builders, including mixtures of pentasodium tripolyphosphate and trisodium nitrilotriacetate in a ratio of these two builders, of 1:10 to 10:1, e.g., 1:1.

The organic surface active component of the aforementioned washing products may be an anionic, non-ionic or amphoteric surface active compound or a mixture of two or more of the foregoing agents may be used.

The anionic surface active agents include those surface active or detergent compounds which contain an organic hydrophobic group and an anionic solubilizing group in their molecular structure. Typical examples of anionic solubilizing groups are sulfonate, sulfate, carboxylate, phosphonate and phosphate.

Examples of suitable anionic detergents which fall within the scope of the anionic detergent class include the water-soluble salts, e.g., the sodium, ammonium, and alkylol ammonium salt of high fatty acids or resin acids containing about 8 to 24 carbon atoms, preferably 10 to 20 carbon atoms. Suitable fatty acids can be obtained from oils and waxes of animal or vegetable origin, e.g., tallow, grease, coconut oil, tall oil and mixtures thereof. Particularly useful are the sodium and potassium salts of the fatty acid mixtures derived from coconut oil and tallow, e.g., sodium coconut soap and potassium tallow soap.

The anionic class of detergents also includes the watersoluble sulfated and sulfonated synthetic detergents having an alkyl radical of 8 to 26, and preferably about 12 to 22 carbon atoms, in their molecular structure. (The term alkyl includes the alkyl portion of the higher acyl radicals.)

Examples of the sulfonated anionic detergents are the higher alkyl mononuclear aromatic sulfonates such as the higher alkyl benzene sulfonates containing from 10 to 16 carbon atoms in the alkyl group in a straight or branched chain, e.g., the sodium potassium and ammonium salts of higher alkykl benzene sulfonates, higher alkyl toluene sulfonates, higher alkyl phenol sulfonates, and higher alkyl naphthalene sulfonates. A preferred sulfonate is linear alkyl benzene sulfonate having a high content of 3- (or higher) phenyl isomers and a correspondingly low content (well below 50%) of 2 (or lower) phenyl isomers, i.e., wherein the benzene ring is preferably attached in large part at the 3 or higher (e.g., 4, 5, 6 or 7) position of the alkyl group and the content of isomers in which the benzene ring is attached at the 2 or 1 position is correspondingly low. Particularly preferred materials are set forth in U.S. Patent 3,320,174.

Other suitable anionic detergents are the olefin sulfonates, including long chain alkene sulfonates, long chain hydroxyalkane sulfonates, or mixtures of alkene sulfonates and hydroxyalkane-sulfonates. These olefin sulfonate detergents may be prepared in a known manner by the reaction of S with long chain olefins containing 8 to 25, preferably 12-21, carbon atoms and having the formula RCH=CHR where R is higher alkyl group of 6 to 23 carbons and R is an alkyl group of 1 to 17 carbons of hydrogen to form a mixture of sultones and alkenesulfonic acids which is then treated to convert the sultones to sulfonates. Other examples of sulfate or sulfonate detergents are parafiin sulfonates containing about -20, preferably about -20, carbon atoms, e.g., the primary parafiin sulfonates made by reacting long chain alpha olefins and bisulfites and parafiin sulfonates having the sulfonate groups distributed along the paraffin chain as shown in U.S. Patents 2,503,280; 2,507,088; 3,260,741; 3,372,188 and German Patent 735,096; sodium and potassium sulfates of higher alcohols containing 8 to 18 carbon atoms such as sodium lauryl sulfate and sodium tallow alcohol sulfate; sodium and potassium salts of u-sulfofatty acid esters containing about 10 to 20 carbon atoms, e.g., methyl a-sulfomyristate and methyl a-sulfotallowate; ammonium sulfates of monoor diglycerides of higher fatty acids, e.g.,

stearic monoglyceride monosulfate; sodium and alkylal ammonium salts of alkyl polyethenoxy ether sulfates produced by condensing 1 to 5 moles of ethylene oxide with one mole of higher (Cg-C18) alcohol; sodium higher alkyl glyceryl ether sulfonates; and sodium or potassium alkyl phenol polyethenoxy ether sulfates with about 1 to 6 oxyethylene groups per molecule and in which the alkyl radicals contain about 8 to about 12 carbon atoms.

The suitable anionic detergents include also the acyl sarcosinates (e.g., sodium lauroylsarcosinate), sodium and potassium salts of the reaction product of higher fatty acids containing 8 to 18 carbon atoms in the molecule esterified with isethionic acid, and sodium and potassium salts of the higher fatty acid amide of methyl taurine, e.g., sodium cocoyl methyl taurate and sodium stearoyl methyl taurate.

Anionic phosphate surfactants in which the anion c solubilizing group attached to the hydrophobic group 1s an oxyacid of phosphorous are also useful in the detergent compositions. Suitable phosphate surfactants are the sodium, potassium and ammonium alkyl phosphate esters such as (R-O) PO M and ROPO M in which R represents an alkyl chain containing from about 8 to about 20 carbon atoms or an alkyl phenol group having 8 to 20 carbon atoms and M represents a soluble cation. The compounds formed by including about one to 40 moles of ethylene oxide in the foregoing esters, e.g.,

[R-O(EtO) 'PO M are also satisfactory.

The particular anionic detergent salt will be suitably selected depending upon the particular formulation and the proportions therein. Preferred salts include the ammonium, substituted ammonium (mono-, diand triethanolammonium), alkali metal (such as sodium and potassium) and alkaline earth metal (such as calcium and magnesium) salts of the higher alkyl benzene sulfonates, olefin sulfonates, the higher alkyl sulfates, and the higher fatty acid monoglyceride sulfates.

The nonionic detergents which are used as the organic surface active component of the washing compositions include all of the nonionic surface active agents discussed heretofore which may be added to the water to form the aqueous nonionic solution used as the granulating agent in the described process.

The water-soluble, ampholytic or amphoteric detergents which can be used in the compositions of this inven tion generally contain a hydrophobic alkyl group of about 8 to 18 carbon atoms, at least one anionic water-solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, or phosphono, and at least one cationic group, e.g., nonquaternary nitrogen, quaternary ammonium, or quaternary phosphonium group, in their molecular structure. The alkyl group may be straight chain or branched and the specific cationic atom may be part of a heterocyclic ring.

Examples of suitable ampholytic detergents include the alkyl beta-aminopropionates, RN(H)C HCOOM; the alkyl beta-iminodipropionates, RN(C H COOM) and the long chain imidazole derivatives having the following formula:

R RzOOOM wherein R is an alkyl group of about 8 to 18 carbon atoms, W is selected from the group of R OH, R OM and R OR COOM, Y is selected from the group consisting of OH, R SO and R O CO- and R OCO R is an alkylene or hydroxyalkylene group containing 1 to 4 carbon atoms, R is selected from the group consisting of alkyl, alkyl aryl and fatty acyl glyceride groups having 6 to 18 carbon atoms in the alkyl or acyl group, and M is a water-soluble cation, e.g., alkali metal, ammonium or allylolammonium. Preferred detergents are sodium N-lauryl beta-aminopropionate, disodium N-lauryl iminodipropionate, and the disodium salt of 2-laurylcycloimidi-l-hydroxyl, l-ethoxyethanoic acid, l-ethanoic acid. Other imidazole detergents are described in U.S. 2,733,068; U.S. 2,781,354 and U.S. 2,781,357.

Examples of suitable ampholytic detergents include the alkyl beta-aminopropionates, RN(I-I)C H COOM; the alkyl beta-iminodipropionates, RN(C H COOM) and the long chain imidazole derivatives having the following formula:

wherein R is an alkyl group of about 8 to 18 carbon atoms, W is selected from the group of R OH, R OM and R OR COOM, Y is selected from the group consisting of OH-, R SO and R OSO R is an alkylene or hydroxyalkylene group containing 1 to 4 carbon atoms, R is selected from the group consisting of alkyl, alkyl aryl and fatty acyl glyceride groups having 6 to 18 carbon atoms in the alkyl or acyl group, and M is a Watersoluble cation, e.g., alkali metal, ammonium or alkylolammonium. Preferred detergents are sodium N-lauryl beta-aminopropionate, disodium N-lauryl iminodipropionate, and the disodium salt of 2-laurylcyclomidium-1-hydroxyl, l-ethoxyethanoic acid, l-ethanoic acid. Other irnidazole detergents are described in US. 2,773,068; U.S. 2,781,354 and US. 2,781,357.

Other suitable amphoteric detergents are the sultaine and betaine types having the following general structure:

wherein R is an alkyl group containing about 8 to 18 carbon atoms, R and R are lower alkyl groups containing 1 to 3 carbon atoms, R is an alkylene or hydroxyalkylene group containing about 1 to 4 carbon atoms, and X is an anion selected from the group consisting of SO (sultaine) and COO= '(betaine). Preferred compounds are l-(myristyl dimethylammonio) acetate and l-(myristyl dimethylammonio)-2-hydroxypropano-3-sulfonate.

Various other materials may be present in the washing products. Thus, materials such as the higher fatty acid amides may be added to improve detergency and modify the foaming properties in a desirable manner. Examples thereof are the higher fatty acid alkanolamides, preferably having 2-3 carbons in each alkanol group attached to a fatty acyl radical containing 10-18 carbons (preferably 10-14 carbons), such as lauric or myristic monoethanolamides, diethanolamides and isopropanolamides.

Other suitable foam builders are the tertiary amine oxides of the general formula R R R N O wherein R is an alkyl radical of about 10 to 18 carbon atoms, R and R are alkyl or hydroxyalkyl groups containing 1 to 3 carbon atoms, and the arrow represents a semipolar bond. Included among the satisfactory amine oxides are laugyl dimethyl amine oxide and myristyl dimethyl amine x1 e.

Fatty alcohols of -18 carbon atoms such as lauryl or coconut fatty alcohols, or cetyl alcohol are suitable additives also. A hydrotropic material such as the lower alkyl aryl sulfonates, e.g., sodium toluene or xylene sulfonates, can assist processing also. In general, these materials and the foregoing foam builders are added in minor amounts, usually from about /2 to 10%, preferably 1 to 6%, based on the total solids.

The mixtures may also contain optical brightening agents of fluorescent dyes (e.g., amounts in the range of about to germicidal ingredients such as halogenated carbonilides, e.g., trichlorocarbanilide, halogenated salicylanilide, e.g., tribromosalicylanilide, halogenated bisphenols, e.g., hexachlorphene, halogenated trifluormethyldiphenyl urea, zinc salt of l-hydroxy-Z-pyridinethione and the like (e.g., in amounts in the range of about to 2%); soil-suspending agents such as sodium carboxymethyl-cellulose or polyvinyl alcohol, preferably both, or other soluble polymeric materials, such as methyl cellulose (the amount of suspending agent being in the range of about to 2%); antioxidants such as 2,6-ditert-butylphenol or other phenolic antioxidant materials (e.g., in amounts in the range of about 0.001 to 0.1%); coloring agents; bleaching agents; and other additives.

A particularly suitable composition, for use as a granular detergent material contains builder salt such as sodium tripolyphosphate and a mixture of a linear alkylbenzenesulfonate, as previously described, soap and a nonionic detergent, with the soap and nonionic detergent being present in minor proportions. About 50 to 1000 parts by weight of builder salt are employed per 100 parts by weight of the mixture of linear alkylbenzenesulfonate, soap and nonionic detergent. The ratios of the amounts of (A) soap, and (B) nonionic detergent, to (C) the total amount of the synthetic anionic sulfonate detergent in the mixture are preferably as follows: AzC, about 1:10 to 1:2, preferably about 1:4 to 1:6, on an anhydrous basis, B:C about 1:10 to 1:3, e.g., about 1:4 to 1:6, on an anhydrous basis. The component (C) is preferably solely a linear alkylbenzenesulfonate although it may comprise a blend of the linear alkylbenzenes'ulfonate detergent with other anionic synthetic sulfate or sulfonate detergents (e.g., olefin sulfonates, paraffin sulfonates having the sulfonate groups distributed along the parafiin chain, or alkyl sulfates) with the alkylbenzenesulfonate constituting say /3, /2 or /3 of this blend.

The following examples are given to illustrate this invention further. In this example, as in the rest of the application, all proportions are by weight unless otherwise specified. Also, in these examples, the pressure is atmospheri c unless otherwise specified.

EXAMPLE 1 0.130 part of the condensation product of 1 mole of nonyl phenol and 9 moles of ethylene oxide are added slowly to 1.020 parts of water in a small tank with stirring at a temperature of 25 C. The thus formed solution is then sprayed onto a continuously agitated premix of 3.455 parts of anhydrous sodium tripolyphosphate and 0.345 part of proteolytic subtilisin enzyme preparation (Alcalase) in a Patterson and Kelly twin shell blender. The premix of phosphate and enzyme is prepared in a powder mixer. Approximately 5 minutes are required to spray the aqueous nonionic solution onto the premix and mixing is continued for about 2 minutes after the spraying is completed. The amount of water in the nonionic solution is equivalent to 100% by Weight of the amount calculated to produce the stable tripolyphosphate hexahydrate.

The anhydrous sodium tripolyphosphate particles used in the premix have the following screen analysis:

YGI'CGIltTG- mammg on mesh was phor-lOHHt- Percent remaming on mesh The volume density of the granules is 0.90 g./cm.

1 part of the above granules is blended in a twin shell blender with 2.5 parts of sodium perborate and 6.5 parts of a spray dried detergent containing about 40% sodium tripolyphosphate, about 12% soap, about 7% ethoxylated polyalkylene glycol nonionic surface active agent (Tergitol XD), about 8% moisture and about 33% sodium sulfate to produce a heavy duty, laundry detergent product.

The laundry product has excellent stability upon aging at room temperature, at 43 C. and in the humid atmosphere achieved at 32 C. and relative humidity.

1 1 Enzyme stability data for the foregoing product is compared with the results obtained on an identical bleach product granulated with water which did not contain any nonionic detergent in Table I below.

TABLE I Percent enzyme 1 After aging at 43 0. Start m;

No nonionic-. 100.0 67 13 Nonionic 100. 101. 0 80. 0

1 Percent enzyme is determined by analyzing for the enzyme content after one week and 4 weeks at 43 C. and then expressing the content as a percentage by dividing same by the enzyme content at the start of the gasltyand multiplying the ratio by 100. (Enzyme content at start equals The foregoing tabulation clearly shows that the use of a solution of nonionic detergent as a granulating agent yields a product containing perborate bleach having enhanced enzyme stability.

EXAMPLE 2 35 parts of the condensation product of one mole of nonyl phenol and 9 moles of ethylene oxide are dissolved in 201 parts of water and sprayed onto a powdered premix of 79 parts of Alcalase proteolytic subtilisin enzyme preparation and 685 parts of anhydrous pentasodium tripolyphosphate in a Griin spraymixer. Again, the amount of water present is suflicient to completely hydrate the phosphate to the stable tripolyphosphate hexahydrate.

The solution of the nonionic surface active agent having a temperature of 25 C. and the premix are continuously dosed into the spray-mixer at outputs of 236 parts per hour and 764 parts per hour respectively for a total output of 1000 parts per hour. The nonionic solution was sprayed through 12 nozzles having an orifice size of 1.2 mm. at a pressure of 6 kg./cm. The product was discharged at a temperature of 32 C. and subjected to quiescent aging for about minutes.

The granules are not prone to excessive dusting and have a desirable appearance. Their volume density is 0.61 g./cm. The particle size of the granules formed in accordance with this process is shown in the following screen analysis:

Percent Opening remaining (1pm.) on mesh One part of the above granules were blended with 2.5 parts of sodium perborate and 6.5 parts of the spray-dried detergent as in Example 1 to obtain a bleach-containing, heavy duty laundry product which exhibits substantially the same stability as the product of Example 1.

EXAMPLE 3 hydration reaction a product having the following screen analysis is obtained.

The volume density is 0.92 g./cm.

1 part of the above granules is blended in a twin shell blender with 9 parts of a spray-dried detergent containing about 26% sodium tridecyl benzene sulfonate, about 30% sodium tripolyphosphate, about 9% moisture and about 35% sodium sulfate to produce an enzyme containing laundry product having good enzyme stability.

The dustiness of the enzyme containing laundry product is determined by subjecting 24 ounces of product to a free fall of 96 centimeters in an enclosed chamber and quantitatively the dust settling during a 30 second period beginning 10 seconds after the free fall. The enzyme containing product has a dust value of 0.085 gram per 1000 grams of product; whereas, an identical product wherein enzyme and inorganic salt are granulated with water in the absence of nonionic has a dust value of 0.198 gram per 1000 grams of product. Since the product produced by the inventive process yields a dust level which is 57% lower than the comparison product, it is clearly apparent that the use of an aqueous nonionic surface active agent as a granulating agent results in a superior enzyme-containing, heavy duty, laundry detergent.

In the above examples, other anhydrous and partially hydrated builder salts may be substituted for anhydrous sodium tripolyphosphate and the amount of water in which the nonionic agent is dissolved adjusted accordingly in order to insure at least substantially complete hydration of the builder salts.

It will be apparent to those skilled in the art that variations and modifications of this invention can be made and that equivalents can be substituted therefor.

We claim:

1. A process for producing a granular enzyme product in which at least 70% of the granules are retained on US. Standard Mesh consisting essentially of about 2% to 50% by weight on a solids basis of a proteolytic enzyme, about 20% to 97% by weight on a solids basis of a particulate water-soluble, hydratable detergent builder salt selected from the group consisting of alkali metal polyphosphates, borates, sulfates, carbonates and silicates and organic nitrilotriacetic acid and ethylene diamine, tetraacetic acid salts and mixtures thereof and about 1% to 25% by weight on a solids basis of a water-soluble, syn thetic, nonionic organic surface-active agent in water which comprises mixing said enzyme in particulate form with said builder salt in particular form and contacting the mixture with an aqueous solution of said nonionic organic surface-active agent, the amount of water in said solution being at least sufiicient to substantially completely hydrate said builder salt.

2. A process as claimed in claim 1 wherein said particulate enzyme preparation and said particulate hydratable salt are premixed and then contacted with said aqueous solution.

3. A process as claimed in claim 1 wherein said particulate enzyme preparation, said particulate hydratable salt, and said aqueous solution are contacted with each other simultaneously.

4. A process as claimed in claim 1 wherein said Water is present in an amount of about to by Weight of the theoretical amount of water in the completely hydrated hydratable salt.

5. A process as claimed in claim 1 wherein said hydratable builder salt is an anhydrous salt.

6. A process as claimed in claim 5 wherein said anhydrous salt is sodium tripolyphosphate and said water is suflicient to form sodium tripolyphosphate hexahydrate.

7. A process as claimed in claim 1 wherein said enzyme is a proteolytic subtilisin enzyme preparation.

8. A process as claimed in claim 1 wherein said nonionic organic surface active agent is the condensation prodnot of an alkyl phenol or a higher alcohol and ethylene oxide.

9. A process as claimed in claim 1 wherein said hydratable salt is a mixture of at least two hydratable salts.

10. A granular enzyme product made according to the process of claim 1.

14 References Cited UNITED STATES PATENTS MAYER WEINBLATT, Primary Examiner W. E. SCHULZ, Assistant Examiner US. Cl. X.R. 195-63; 424--90 

